How to Select Proper Press Felt Size and Dimensions

Factors to Consider in Press Felt Selection and Design

The selection of press felt depends on the paper grade, basis weight, surface finishing requirements, paper machine configuration, operating environment, and existing felt cleaning systems. Proper felt design and selection should be based on the technical parameters of the paper machine and the efficiency and energy-saving performance requirements of the press section.

By optimizing the process and technical parameters according to actual machine operating conditions, press felt can significantly improve press section dewatering efficiency, increase wet sheet density, reduce sheet breaks, and ensure stable high-speed paper machine operation.

To ensure efficient and energy-saving performance of the press section, the following factors should be considered when selecting and designing press felt.

The Choice of Press Felt Weight

The weight of press felt should be determined according to the press configuration, felt position, paper grade, washing conditions, and vacuum level. Excessive felt weight may increase moisture retention, reduce machine speed, increase flow resistance, accelerate felt contamination, and increase vacuum pump energy consumption. Insufficient felt weight may result in excessive permeability, unstable vacuum operation, poor wear resistance, rough sheet surface, and increased felt marking.

Selection of Press Felt Size

Press felt are a type of fabric, and their dimensions after production, installation on paper machines, and use may vary slightly. Therefore, when determining the order size, it should be appropriate. The confirmed order size should be the size under tension.

Selection of Press Felt Length

Press felt length directly affects felt strength requirements. Longer felts require higher tensile strength. When measuring felt length on the paper machine, the tensioner is typically positioned at 2/5 to 1/2 of its tensioning range. A non-stretch measuring line is used to determine the actual felt circumference, which serves as the ordering length. Ordering too long or too short will reduce installation efficiency and usage effectiveness.

Selection of Press Felt Width

Press felt width is determined based on the press roll face width. If the felt ordered is too wide, it is easy to cause the edges of the felt to be worn out. After the edges of worn out, the exposed bottom mesh (base layer) threads are easily thrown into the wet paper sheet, causing frequent paper breakage and tearing of the felt. If the paper making felt ordered is too narrow, it will cause instability during operation, easy deviation and air leakage. After the standard line is slightly skewed, the press felt is easily narrowed and cannot support the entire paper sheet. The width of the felt being too wide or too narrow can affect the normal operation of the paper machine.